Imaging current flow in the brain during transcranial electrical stimulation

Images show (left to right for two different stimulations) the standard MR image, measured electrical current distribution overlaid on MR image, measured electrical current density alone, and simulated current distribution.

Scientists measured the first in vivo images of stimulated current within the brain using an imaging method that may improve reproducibility and safety, and help understand the mechanisms of action of electrical stimulation.

First, some background

External electrical stimulation of the brain may improve cognitive, motor and memory performance, assist stroke rehabilitation and treat epilepsy. Ideally, electrical stimulation should guide current to a desired brain location. But the path current in the brain is unknown, but applications rely upon simulating possible current distribution, so the underlying mechanisms of action remain unclear.

What did the scientists discover?

A MagLab user collaboration among three institutions used a novel application of magnetic resonance imaging (MRI) to measure the first images of the electrical current distribution within the living brain while the brain is experiencing transcranial electrical stimulation.

Why is this important?

Transcranial electrical stimulation has been shown to improve cognitive, motor and memory performance in healthy people. There is evidence that it may also provide new treatments for stroke rehabilitation and epilepsy. However, transcranial electrical stimulation is not well understood, in part because, before this study, no one could image the electrical current distribution in brains experiencing transcranial electrical stimulation. This new MRI method will be useful for improving the reproducibility and safety of transcranial electrical stimulation, as well as for advancing our ultimate understanding of the mechanisms that cause transcranial electrical stimulation to work.

Why did they need the MagLab?

MRI research capabilities in the MagLab's AMRIS Facility developed this imaging method, which required the construction of control hardware interfaced to a 3T MRI system, as well as the development of data acquisition and data processing methodologies.